Turbine rotated antenna with electromagnetic answer-back means



A. ALFORD 2,595,912 TURBINE ROTATED ANTENNA WITH ELECTROMAGNETICANSWER-BACK MEANS May 6, 1952 Filed April 9, 1946 FIG-2 INVENTOR ANDREWALFOR D AT TORNEY Patented May 6, 1952 TURBINE ROTATED ANTENNA WITHELEC- TROMAGNETIC AN SWER-BACK MEANS Andrew Alford, Cambridge, Mass.,assignor'to the United States of Secretary of War America asrrepresentedby the Application April 9, 1946, Serial No. 660,603

Claims. 1

This invention relates in general to mechanical-electrical apparatus andmore particularly to a rotatable system suitable for installation on theexterior of a submarine.

It is often necessary to install a rotatable system such as a rotatableradar antenna or a rotatable direction finding antenna on the exteriorof a submarine. One method of rotating the antenna is to use a driveshaft driven by an electric motor, both shaft and motor being located onthe exterior of the submarine. A water pressure seal is used on thedrive shaft-to-motor connection to prevent leakage when the submarinesubmerges. Such seals may be used where the speed of rotation iscomparatively low (i. e. of the order of R. P. M.), although the sealsmay leak at great depths. However, these seals are not practical atspeeds of the order of 300 R. P. M., such as are required for microwavedirection finding.

Accordingly an object of the present invention is to produce a rotatableantenna system suitable for installation on the exterior of a submarine.

A further object of the present invention is to produce such a rotatableantenna system which may be operated at a high rotational speed.

Other objects and advantages of the invention will be apparent duringthe course of the following description.

One embodiment of the invention involves a radical departure from thecustomary antenna drive mechanism. Essentially the rotating drive is awater turbine driven from the high pressure water system in thesubmarine. A one way valve is placed in the pipe from the high pressurewater system to the turbine nozzle, and prevents a reverse fiow of waterwhen the submarine is submerged. The shaft of the water turbine drives amicrowave direction finding antenna which is affixed to its upper end.The indication of the angular rotation of the antenna is furnished by amagnetically coupled synchronous system which includes a selsyngenerator in a hermetically-sealed pressure-tight selsyn housing. Theshaft of the selsyn generator and the lower end of the turbine shaft areboth provided with permanent magnets which are separated by a brassplate. The magnetic coupling between the magnets serves to rotate theselsyn generator in synchronism with the antenna. The electrical outputof the selsyn generator may be transmitted to the interior of thesubmarine in the customary manner.

l3 arranged to tangentially In the accompanying drawing forming a partof this specification,

Fig. 1 is a simplified partially cross-sectioned view illustrating oneembodiment of the invention and,

Fig. 2 is a simplified cross-sectional view taken on the line 2-2 ofFig. 1. I

In Fig. 1, wherein is illustrated one embodiment of the invention,numeral l0 designates the surface of the submarine. A water turbine ll(best understood by reference to Fig. 2) consists of an impeller wheelI2 and a converging nozzle drive the impeller wheel. The impeller wheel[2 is constructed of two circular supporting plates l4 between whichareafiixed impeller vanes l5. The nozzle I3 is connected (connection notshown) to the high pressure water system within the submarine. A one wayvalve V is inserted in the connection from nozzle L3 to the highpressure water system and serves to prevent a reverse flow of water whenthe submarine is submerged. Numeral l6 designates a housing afiixed tosurface 10 which serves to protect the turbine II and to retain thewater output from the turbine I l An outlet pipe H at the bottom ofhousing l6 serves to exhaust the water output from the turbine.

The turbine ll rotates a drive shaft 18 (not cross-sectioned) which iskeyed to the impeller wheel (key not shown). The drive shaft l8 rotatesin a water-lubricated rubber bearing 19 (not cross-sectioned). Waterinlet '20 to hearing I9 is supplied with water from the high pressurewater system (connection not shown). The downward thrust of shaft [8 istaken by an end bearing 2! which is affixed to the top ofhermetically-sealed selsyn housing 22.

The antenna is a standard type of direction finding antenna whichincludes a cylindrical parabola reflector 23 affixed to shaft I8 withits axis at 45 to the axis of the shaft. The periphery of the reflector23 is determined by the intersection of a cylindrical parabolic surfacewith its axis inclined at 45 to the axis of the shaft l8 with acylindrical surface having its axis along the axis of shaft l8. Anelectromagnetic horn (not shown) having a circularly polarized responseis disposed at point 24 on the axis of shaft I8. The response of thehorn is substantially constant for all signals in the planeperpendicular to the axis of shaft I8. It is to be understood that thedirection finding antenna formed by reflector 23 and the circularlypolarized horn is only one of many antennas which may be affixed to theshaft [8.

The indication of the angular rotation of reflector 23 is furnished bythe synchronous system 25 which includes a selsyn generator 26 having apermanent magnet 21 affixed to its shaft. The selsyn generator isenclosed in hermeticallysealed selsyn housing 22. Synchronous drive between shaft I8 and selsyn generator 26 is effected by the magneticcoupling between magnet 21 and a similar magnet 28 which is affixed atthe lower end of shaft 18. A brass plate 29 forming the top of selsynhousing 22 permits close magnetic coupling between magnets 21 and 28.However other suitable materials may be used instead of brass, ifdesired. The electrical output of selsyn generator 26 is transmittedthrough cable 30 and may be transmitted to the interior of the submarinethrough an electrical connector box in the customary manner.

It will be apparent that there may be deviations from the invention asdescribed which still fall fairly within the spirit and scope of theinvention.

Accordingly all such deviations are claimed which fall fairly within thespirit and scope of the invention as indicated in the hereinafterappended claims.

What is claimed is:

1. In a submersible radar antenna system for a submarine, a housingattached to the exterior of said submarine, a vertical shaft passingthrough the upper end of said housing, a parabolic reflector attached tothe upper end of said vertical shaft, a hydraulic impulse wheel withinsaid housing and attached to said vertical shaft, a nozzle positioned insaid housing adjacent said impulse wheel to direct a fluid streamthereon from the water system of said submarine, a first permanentmagnet attached to said vertical shaft, an electrical angular positiontransmitter within said housing coaxially with said vertical shaft, asecond permanent magnet attached to said angular position transmitterand positioned adjacent said first permanent magnet, a sealed cover forsaid angular position transmitter and said second permanent magnethaving a diamagnetic portion at least between said first and secondpermanent magnets whereby said impulse wheel drives said parabolicreflector and the position thereof is transmitted through said sealedcover to said angular position transmitter by said permanent magnets.

2. The structure claimed in claim 1 wherein said electrical angularposition transmitter comprises a selsyn transmitter.

3. In a rotatable antenna system for a submarine, driving shaft means, awater turbine including an impeller wheel connected to said drivingshaft means, a converging nozzle adjacent said impeller Wheel connectedwith the high pressure water system in the submarine for directing astream of water onto said impeller wheel to rotate said drive shaftmeans, and valve means for preventing flow from said nozzle back to saidhigh pressure water system, an antenna rotated by said drive shaftmeans, and means for indicating the angular rotation of said antenna.

4. In a rotatable antenna system for submarines, drive shaft means, animpeller wheel carried by said drive shaft means, an antenna driven bysaid drive shaft, a nozzle adjacent said impeller wheel connected to thehigh pressure water system of the submarine fOr directing a stream ofwater thereon to rotate said antenna, and valve means for preventingwater flow from said nozzle to said high pressure water system of saidsubmarine.

5. In a rotating antenna system for submarines, a housing attached tothe exterior of said submarine, a drive shaft extending through saidhousing, an impeller wheel mounted on said drive shaft within saidhousing, a parabolic reflector mounted on the outer end of said driveshaft, a nozzle within said housing adjacent said impeller wheelconnected to the high pressure water systern of said submarine to directa stream of water onto said impeller wheel to rotate said reflector, andmeans to prevent flow from said turbine to said high pressure watersystem.

ANDREW ALFORD.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 1,025,611 Doble May 7, 19121,028,554 Doble June 4, 1912 1,303,729 Rogers May 13, 1919 1,308,435Maire July 1, 1919 1,962,659 Kautz June 12, 1934 2,219,844 Lotter Oct.29, 1940 2,407,310 Lundy Sept. 10, 1946 2,410,827 Langstroth et a1. Nov.12, 1946

